Margins and Padding

:padding - around the image source and included in the css coordinates of the sprite.

:margin - around the image source but NOT included in the css coordinates of the sprite.

The :margin option is most useful to avoid the bleeding that might occur when the browser scales
to support increased text size or zooming (e.g ctrl+/ctrl-). Depending on the scale factor, the
browser may decide to use an extra pixel of your source image leading to the next image bleeding through.

This can now be avoided using the :margin => 1 option to ensure a gap is included around
the source image to take into account any bleeding that might occur (usually a value of 1 or 2 pixels is adequate)

Support for :hover pseudo classes

If you want to specify a pseudo class such as :hover for some of your images, the library will now
map -- (double dash) to a colon : in any source image filename. For example, with the following files:

Support for per-image custom selector

If you want to specify a custom selector for each individual image, you can simply name
the image files accordingly - the library will map __ (double underscore) to a single
space ` ` in any source image filename. For example, with the following files: